Blasting glass can help boost your bottom line. Find out how sandblasting glass is the same and different from other substrates. Can you sandblast with the best of them?
If you’ve got the equipment and the skill to blast stone, ceramic or wood, then there’s no reason not to consider expanding your business to include blasting glass.
Etching is a method to produce frosted designs on the surface of glass, carve a design deep into glass or create a delicate shaded image on glass. Advanced etchers can combine these three techniques for strikingly artistic signage that offers clients a touch of class in a crowded marketplace.
“Sophisticated companies don’t want neon signs. They want more subtle signage,” says Ric Banchero, principal of Bancheros Glass & Etching in Kent, Wash. “That’s where glass etching comes in. There’s an aesthetic quality and beauty to glass art.”
That aesthetic quality and beauty can yield more profitable signs. But there are a few facts you need to know before you begin blasting glass. After all, glass does require some special handling because you can’t patch over your mistake. And although the basic techniques are the same, there are some small differences that can make a big difference between success and failure.
Choosing the Right Materials
Basic glass etching is a four-step process: (1) cover the surface of the glass with resist, (2) trace your design on the resist and cut it out with a stencil knife (or use a stencil) (3) remove the portions of the resist from the glass you want to etch, and (4) blast the exposed areas of the glass. Voila! You’ve just surface etched glass.
While you may have the equipment in-house, you’ll need glass-friendly resist and abrasive to achieve maximum results. Resist is the rubber/vinyl material that “resists” the impact of the blast to protect the glass underneath. There are many types on the market, but experts say a thickness of four to six mils is best for surface etching or shading. Carving may require eight to 25 mil thick resist. As a general rule of thumb, the more pressure you use and the faster you want to carve, the thicker the resist.
“Using the wrong resist material can create problems if you are trying to get depth,” says Derek Lindeborg, vice president of On-Site Systems Glass Etching in Atlanta. “You can end up blasting through the resist and then you have to throw the glass away. It’s a very expensive lesson.”
The right abrasive is also critical to a quality etch. The abrasive has to be as hard as or harder than the glass and the particles have to be rough, with sharp corners and edges. Norm Dobbins, a 25-year glass blasting veteran with a studio in Sante Fe, N.M., says glass beads don’t work because they are round and smooth. And sand has three downsides it’s hazardous to breathe, the particles dull quickly and you can’t get sand in a fine grit. Most etching is done with grit sizes of 120, 150 or finer to give a beautiful, smooth finish to the etching.
“The best abrasive is a silicon carbide because it is hard and reusable,” says Dobbins, who is also founder of Aliento Glass School and peddles how-to books and videos on the topic. “The next best choice is aluminum oxide, but it creates a lot of static electricity in the cabinet. That static can cause constant shocks and also causes the dust to cling to the back of the glass, making it difficult to see what you are etching. This is especially distracting when you are trying to use the shading technique.”
Understanding the Techniques
One of the biggest differences between blasting glass and blasting other substrates common to the sign industry, is the more advanced techniques. Learning these techniques is the biggest challenge in transitioning from wood to glass because there’s not a body of generally accepted guidelines to follow and there’s more to glass than meets the eye.
Surface etching is done in one stage and produces a positive and negative (black and white) design and is the easiest technique for most sign makers to adapt to. Carving and shading, however, requires a greater learning curve. Carving is blasting deep into the glass to produce a three-dimensional etching. Even within carving there are multiple techniques, including single state, two stage, multi-stage and freehand. Single stage carving blasts the surface etching design deep into the glass and separates elements with clear spaces. In stage two or multi-stage carving the resist is removed bit by bit in a definite sequence to give even greater depth.
“Elements of a two stage or multi-stage carving design do not have to be separated from each other as they do in surface etching because they are removed at different times and blasted to different depths,” says Dobbins. “These different depths are what give the necessary visual separation between elements.”
Like surface etching, shading blasts only the glass surface, but the elements in the design are blasted to different shades of gray rather than strictly the solid white color produced in surface etching. Etching the surface to varying densities of less than 100 percent causes different degrees of shading. “Elements of the shading design can all touch, as they can with a carving design, because the visual separations between elements are created by the stage blasting process,” Dobbins says. “Shaded etching looks very much like airbrushing, with flowing tones of light and dark indicating shape and contour.”
Glass etchers who can combine all three techniques enjoy the strengths and weaknesses of each one to create the most sophisticated possible designs. Even more advanced techniques include combining etching with stained glass, tempered glass, glue chips or glass blowing.
For example, blasting the reverse side of a mirror can produce some interesting effects. If you blast the reflective surface you will get a double-image that reflects off the backside of the glass and adds depth. But experts say mirrored surfaces scratch easily, and one scratch looks like two scratches. The key to avoiding mistakes is in the correct use of the resist and to seal the finished surface with clear Krylon to prevent chipping.
Safety and Selling
Regardless of what technique you use, experts stress the importance of safety equipment like goggles, respirators, earplugs and a blasting hood. Flying particles of glass can cause permanent lung damage so cartridge type respirators are not sufficient. You need a separate air supplied hood and air pump certified for breathing air in the blast room. Always follow the manufacturer’s recommended procedures for proper maintenance of the blasting cabinet and its dust collector.
There are crystal clear opportunities for sign makers to market etched glass products. Restaurants, retail business, hotels and corporate headquarters that want an upscale image are prime targets. You can blast doors, interior glass walls, awards, or even drinking glasses. The possibilities are almost endless. Since glass costs less than many types of wood, you can increase your profits before you even begin.
“The best way to market glass etching and make a profit at it is to introduce etched products as a part of your product line to your existing customers,” Dobbins says. “It’s easier to sell an additional product to an existing customer than to go out and get a new customer for a new product.”
As seen on signindustry.com